Willie Nelson has a lot of friends. So, when he and his traveling family hit Boston Tuesday for a concert with Alison Krauss, Nelson made sure to call on one of those famous friends to spend some time with his country legend pal onstage.

Clad in jeans and a T-shirt, Johnny Depp joined the legend to play electric guitar throughout the entire set at the Blue Hills Bank Pavilion on the Boston waterfront. Nelson didn't announce that the star of Charlie and the Chocolate Factory was on stage while introducing the band, the 81-year-old legend kept it on a first-name basis.

Earlier that day, Depp, 51, and costar Juno Temple filmed scenes on the South Boston set of Black Mass, in which he plays notorious Boston gangster Whitey Bulger.